add PdhLookupPerfNameByIndex wrapper

bindings/java/src/jni/win32/pdh.c

@@ -401,6 +401,23 @@ JNIEXPORT jobjectArray SIGAR_JNI(win32_Pdh_pdhGetObjects)
     return array;
 }
 
+JNIEXPORT jstring SIGAR_JNI(win32_Pdh_pdhLookupPerfName)
+(JNIEnv *env, jclass cur, jint index)
+{
+    TCHAR path[8192];
+    DWORD len = sizeof(path);
+    PDH_STATUS status =
+        PdhLookupPerfNameByIndex(NULL, index, path, &len);
+
+    if (status == ERROR_SUCCESS) {
+        return JENV->NewStringUTF(env, path);
+    }
+    else {
+        win32_throw_exception(env, get_error_message(status));
+        return NULL;
+    }
+}
+
 #ifdef __cplusplus
 }
 #endif

bindings/java/src/org/hyperic/sigar/win32/Pdh.java

@@ -101,6 +101,12 @@ public class Pdh extends Win32 {
         return counters.map;
     }
 
+    public static String getCounterName(int index)
+        throws Win32Exception {
+
+        return pdhLookupPerfName(index);
+    }
+
     /**
      * @deprecated
      * @see #getRawValue(String path)
@@ -163,6 +169,8 @@ public class Pdh extends Win32 {
         throws Win32Exception;
     private static final native String[] pdhGetObjects()
         throws Win32Exception;
+    private static final native String pdhLookupPerfName(int index)
+        throws Win32Exception;
 
     /**
      * Main method for dumping the entire PDH

bindings/java/src/org/hyperic/sigar/win32/test/TestPdh.java

@@ -68,10 +68,14 @@ public class TestPdh extends SigarTestCase {
         };
         String last = null;
         for (int i=0; i<keys.length; i++) {
-            String index = (String)counters.get(keys[i]);
+            String name = keys[i];
+            String index = (String)counters.get(name);
             assertFalse(index.equals(last));
-            traceln(keys[i] + "=" + index);
+            traceln(name + "=" + index);
             last = index;
+            String lookupName =
+                Pdh.getCounterName(Integer.parseInt(index));
+            traceln(name + "=" + lookupName);
         }
     }